Protected collapsible tubing



p 18, 1956 w. E. REJESKI PROTECTED COLLAPSIBLE TUBING Filed Oct. 8, 19531/11/10 I will 1/1 val/A III/I) 0:.

INVENTOR. Wmuem E REJEsm ATTORNEYS United States Patent PROTECTEDCOLLAPSIBLE TUBING William E. Rejeski, Farmington, Conn., assignor toThe Wrremold Company, West Hartford, Conn., a corporation of ConnecticutApplication October 8, 1953, Serial No. 384,987 7 Claims. 01. 138-53)This invention relates to improvements in collapsible tubing and moreparticularly it relates to collapsible tubing formed of metallicor'other relatively stiff and springy forming and supporting stripswound in a helical spiral and between the convolutions of which is astrip of fabric, plastic or other flexible material.

Tubing of this sort as heretofore formed has sometimes been made of atrough-shaped metallic helical-spiral strip, in the trough of whichoverlapping edges of a spirally wound fabric strip was pushed by acontinuous wire, the wire and strip being interlocked in the trough bythe edges of the metal strip being pressed together. An example of thatsort of tubing is disclosed in the A. E. Chernack Patent 2,337,373 datedDecember 21, 1943, and owned by the assignee of this application.

Tubing of that patent sometimes would wear at the point where the fabricjoined the metal spiral strip. The ability of the fabric to move andflex freely at that place and also abrasion of the fabric as thatportion of it in front of or next to the spiral strip rubbed againstrough surfaces fostered wearing of that portion.

Therefore, it is an object of this invention to provide a new tubingconstruction which will overcome the tendency of the flexible strip towear in the manner and at the place indicated.

Another object is to provide a new tubing construction which, whileovercoming the aforesaid defects, will not require more than threeelements.

Another object is to provide a new tubing construction wherein the thirdelement is formed to cooperate with the flexible strip and thehelical-spiral forming-strip (a) during manufacture of the tube to causeinter-engagement of the latter two and, (b) in the final product toovercome the aforesaid wearing defects.

Other objects and advantages of the invention will appear as it isdescribed in connection with the accompanying drawing.

In the drawing:

Figure 1 is a perspective view partly broken away and partly in sectionof tubing embodying the invention.

Figure 2 is an enlarged detailed view showing, in longitudinal section,two convolutions of the tubing of Figure 1.

Figure 3 is a fragmentary view showing in section two overlapping edgesof adjacent convolutions of the flexible strip before being combinedwith the metallic strip.

Referring to the drawing, the tubing comprises a helical strip of metal,such as soft steel or the like, or other suitable resilient materialwhich can be bent in the helical form and is resilient enough forcompression and expansion like a spring while yet being stiff enough toconstitute and to maintain the tube permanently in tubular form. Thestrip 153 is bent into channel or U-shaped cross-section and has the topedges of its side portions bent oppositely outward forming wings 12 and14.

in the trough between the wings 12 and 14, overlapping edge portions ofadjacent convolutions 16 and 18 of a 'ice helically wound strip offlexible material are pressed in such a way that both edges of theportion of the strip are extended over one edge of the metal strip 10and down into the trough and up and out over the opposite edge. Theflexible strip constitutes a cover for the tube and may be of treated oruntreated fabric, plastic or other flexible material.

To hold the fabric in the trough and also to protect the fabric where itengages the wings 12 and 14 of the strip 10, a channel or U-shaped strip29 has its channel portion lying in the trough of the strip 16 upon theoverlapping edges of the fabric strip. The strip 20 may be of the sameor different material than the strip 10. Preferably it will be ofmaterial which is easily bent and formed into the desired shape. Theedges of the side portion of the protective strip 26 are bent oppositelyoutward forming wings 22 and 24 which lie upon the fabric which in turnlies upon the wings 12 and 14 of the strip 1b.

In order to lock the inter-engaging portions of the several strips, themouth of the U-shaped portion of the strips 19 and 23 may be pressedclosed. Also the edges of the wings 22 and 24 are reversely bent to lieon the outer surfaces of the flexible strip. This provides a smoothmarginal edge on the strip 2 1); and simultaneously it more firmly holdsthe fabric between the wings of the strips 10 and 2% because the innerwings 12 and 14 press the fabric against the folded edges 23 and 25 ofthe wings 22 and 24.

Because of the cover provided by the securing and protective strip 26over the flexible strip where the latter joins the forming strip 19, theflexible strip is protected against wear at that point. Thus flexing isprevented at that point and abrasive action cannot occur when the tubingis moved over a rough surface or over relatively smooth surfaces whichin time would tend to wear the fabric in the same way as a roughsurface.

If it is desired to provide tubing of stiffer nature or more resistantto bending or flexing axially than tubing having only the forming andthe protective strips, an additional element may be provided such as thespring wire 31). This Wire may be inserted in the trough of theprotective strip 2% during the formation of the tubing. Generally thisstiffening wire will not be needed when the forming strip it; is made ofsoft steel or like springy material. Nevertheless, the wire may bedesirable in some tubing constructions when the forming strip 10 has alesser springiness or is made of material which while flexible is notsufficiently springy to provide the desired ability of the tubing toreturn to fully expanded form free of outside compressive forces.

The element 36 may also be used in non-springy or non-metallic form incase it is desired to make use of its binding action alone.

Many modifications within the scope of the invention will occur to thoseskilled in the art. Therefore, the invention is not limited to theprecise configuration and formation illustrated and described.

What is claimed is:

1. Tubing comprising an inner strip of trough-shaped cross section woundin a spiral, a spirally wound covering strip, said covering strip havingadjacent edges overlap ping along said spirally wound inner strip, and aspirally wound protective strip of trough-shaped cross section securingsaid overlapped edges in said spirally wound inner strip and havingouter edge portions oppositely extending to protect said covering stripin the area over the edges of said spirally wound inner strip.

2. Collapsible tubing comprising an inner strip of resilient materialwhich is trough-shaped in cross section and wound in a spiral, aspirally wound flexible covering strip, said covering strip havingadjacent edges overlapping along said spirally wound inner strip, and aspirally wound protective strip of trough-shaped cross section securingsaid overlapped edges in said spirally wound inner strip and havingouter edge portions oppositely extending to protect said covering stripin the area over the edges of said spirally wound inner strip.

3. Tubing comprising an inner strip of trough-shaped cross section woundin a spiral, a spirally wound covering strip, said covering strip havingadjacent edges overlapping along said spirally Wound inner strip, and aspirally wound protective strip of trough-shaped cross section securingsaid overlapped edges in said spirally wound inner strip and havingouter edge portions oppositely extending to protect said covering stripin the area over the edges of said spirally wound inner strip, saidprotective strip having said outer edge portions reversely bent inwardlyto provide a smooth marginal edge and a firmer grip of said overlappingedges between said spirally wound inner and said protective strips.

4. Collapsible tubing comprising an inner strip of resilient materialwhich is trough-shaped in cross section and Wound in a spiral, aspirally wound flexible covering strip, said covering strip havingadjacent edges overlapping along said spirally wound inner strip, and aspirally wound protective strip of trough-shaped cross section securingsaid overlapped edges in said spirally wound inner strip and havingouter edge portions oppositely extending to protect said covering stripin the area over the edges of said spirally wound inner strip, saidprotective strip having said outer edge portions reversely bent inwardlyto provide a smooth marginal edge and a firmer grip of said overlappingedges between said spirally wound inner and said protective strips.

5. Tubing as claimed in claim 4 having a binding means securing saidoverlapped edges and protective strip in the trough of said spirallywound inner strip.

6. Tubing as claimed in claim 1 having a binding means securing saidoverlapped edges and protective strip in the trough of said spirallywound inner strip.

7. Tubing as claimed in claim 6 wherein the covering strip is offlexible material and the binding means is of resilient materialpermitting collapse and tending to restore the tubing to full length.

References Cited in the file of this patent UNITED STATES PATENTS753,230 Calcutt Mar. 1, 1904 2,337,373 Chernack Dec. 21, 1943 2,337,374Chernack Dec. 21, 1943

